Fix #4582: Safebooru should not block "censored" tag

* Remove the default list of blocked tags in safe mode.
* Change it so that tags that are blocked in safe mode are filtered out
  at the database level rather than at the html level.

app/logical/post_query.rb

@@ -38,7 +38,9 @@ class PostQuery
 
   # Perform a search and return the resulting posts
   def self.search(search, ...)
-    PostQuery.normalize(search, ...).with_implicit_metatags.posts
+    post_query = PostQuery.normalize(search, ...)
+    post_query.validate_tag_limit!
+    post_query.with_implicit_metatags.posts
   end
 
   def initialize(search_or_ast, current_user: User.anonymous, tag_limit: nil, safe_mode: false)
@@ -71,12 +73,12 @@ class PostQuery
   end
 
   def posts
-    validate!
+    validate_metatags!
     builder.posts(to_cnf)
   end
 
   def paginated_posts(...)
-    validate!
+    validate_metatags!
     builder.paginated_posts(to_cnf, ...)
   end
 
@@ -189,9 +191,10 @@ class PostQuery
 
   # Implicit metatags are metatags added by the user's account settings. rating:s is implicit under safe mode.
   def implicit_metatags
-    metatags = []
+    return [] unless safe_mode?
-    metatags << AST.metatag("rating", "s") if safe_mode?
+
-    metatags
+    tags = Danbooru.config.safe_mode_restricted_tags.map { |tag| -AST.tag(tag) }
+    [AST.metatag("rating", "s"), *tags]
   end
 
   # XXX unify with PostSets::Post#show_deleted?
@@ -272,18 +275,13 @@ class PostQuery
   end
 
   concerning :ValidationMethods do
-    def validate!
-      return if is_empty_search? || is_simple_tag?
-
-      validate_tag_limit!
-      validate_metatags!
-    end
-
     def validate_tag_limit!
+      return if is_empty_search? || is_simple_tag?
       raise TagLimitError if tag_limit.present? && term_count > tag_limit
     end
 
     def validate_metatags!
+      return if is_empty_search? || is_simple_tag?
       return if metatags.empty?
 
       order_metatags = select_metatags(*ORDER_METATAGS)

app/logical/post_sets/post.rb

@@ -36,7 +36,7 @@ module PostSets
     # The description of the page for the <meta name="description"> tag.
     def meta_description
       # XXX post_count may be nil if the search times out because of safe mode
-      if normalized_query.is_simple_tag? && post_count.present?
+      if post_query.is_simple_tag? && post_count.present?
         humanized_count = ApplicationController.helpers.humanized_number(post_count, million: " million", thousand: " thousand")
         humanized_count = "over #{humanized_count}" if post_count >= 1_000
 
@@ -106,7 +106,8 @@ module PostSets
     end
 
     def posts
-      @posts ||= normalized_query.paginated_posts(page, includes: includes, count: post_count, search_count: !post_count.nil?, limit: per_page, max_limit: max_per_page).load
+      post_query.validate_tag_limit!
+      normalized_query.paginated_posts(page, includes: includes, count: post_count, search_count: !post_count.nil?, limit: per_page, max_limit: max_per_page).load
     end
 
     # @return [Integer, nil] The number of posts returned by the search, or nil if unknown.
@@ -197,6 +198,6 @@ module PostSets
       end
     end
 
-    memoize :page_title
+    memoize :page_title, :posts
   end
 end

app/models/post.rb

@@ -1336,6 +1336,7 @@ class Post < ApplicationRecord
       # @return [ActiveRecord::Relation<Post>] the set of resulting posts
       def user_tag_match(query, user = CurrentUser.user, tag_limit: user.tag_query_limit, safe_mode: CurrentUser.safe_mode?)
         post_query = PostQuery.normalize(query, current_user: user, tag_limit: tag_limit, safe_mode: safe_mode)
+        post_query.validate_tag_limit!
         post_query.with_implicit_metatags.posts
       end
 

config/danbooru_default_config.rb

@@ -253,7 +253,7 @@ module Danbooru
 
     # Tags that are not visible in safe mode.
     def safe_mode_restricted_tags
-      restricted_tags + %w[censored condom nipples nude penis pussy sexually_suggestive]
+      []
     end
 
     # If present, the 404 page will show a random post from this pool.